This is a 371 of PCT/EP00/00061, which was filed Jan. 7, 2000.
This invention relates to a method for closing packages made of flexible material such as bags, tubes or the like, wherein a portion of the packaging material is gathered to form a neck and the same is inserted into an open, substantially U-shaped closure clip with a clip base and clip legs on both sides, whereupon the legs of the closure clip are bent around the neck in the form of a ring. The invention furthermore relates to a device for performing this method, comprising a matrix for holding the open closure clip and a punch movable towards the matrix for bending the clip legs around the neck of the packaging material.
From DE 38 44 052 C1, for instance, there is known such closing of for instance sausage ends including the closure clips and closing tools used for this purpose. The closure clips prebent to form a U are hanging on each other by means of webs crimped at the leg ends and form a strand of clips which can be supplied as a magazine, from which strand of clips the respective closure clip is cut offxe2x80x94in the middle of the connecting web with the next closure clip in the strand of clipsxe2x80x94during the working stroke of the closing tools. During the closing operation, the web end portions are urged against the outside of the clip legs and together with the same are bent around the neck of the packaging material, the leg ends and leg portions being urged against each other and thereby upset, so that there is obtained a ring pressing together the neck of the packaging material as tightly as possible.
This technology has been quite successful. However, in certain cases, especially in the case of relatively rigid packaging material, malfunctions can occur due to the fact that the neck, which has been formed for instance by displacement shears and has been inserted into the still open closure clip, slightly snaps back and when the clip is subsequently closed, the same damages the packaging material so that the package, for instance a sausage casing, becomes leaky.
This deficiency should be eliminated by means of the invention. The method of the invention consists in that after inserting the neck and before bending the clip legs the neck is urged towards the plane of the clip base axially beside the closure clip. In this way, the neck is prevented from deploying towards the opening of the clip not yet closed, and during the subsequent closing operation the bent legs of the closure clip are prevented from squeezing and damaging a fold of the neck. There can also be used a closure clip with shorter legs, which especially in the case of a thin neck of the packaging material requires less upsetting work during the closing operation and promotes a tight closure of the neck.
The device provided for performing this method is characterized by at least one hold-down device laterally attached to the punch in direction of the neck, the effective area of said hold-down device protruding beyond the working surface of the punch in direction of movement thereof by a small amount. This amount may be about 1 to 5 mm, preferably it is 2 to 3 mm. Further preferred embodiments of this device are also subject-matter of sub-claims.